Aircraft training apparatus



69 w w @lvmv Jan. 2, 1945. R. c. DEHMEL AIRCRAFT TRAINING APPARATUS Filed Dec. 20 1941 16 Sheets-Sheet l Jan. 2, 1945. R c, DEHMEL AIRCRAFT TRAINING APPARATUS Filed Dec. 20 1941 16 Sheets-Sheet 2 INVENTOR QQN o Jan. 2, 1945.

R. CVDEHMEL AIRCRAFT TRAINING APPARATUS 1s Shets-Sheet s Filed Dec. 20

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R. C. DEHMEL AIRCRAFT TRAINING APPARATUS Filed Dec. 20, 1941 7'0 FIG. 7

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16 Sheets-Sheet 4 Jan. 2, 1945. R, c, DEHMEL 2,366,603

AIRCRAFT TRAINING APPARATUS Filed Dec. 20, 1941 16 Sheets-Sheet 5 TO FIG W A To FIG so, 444 "11,1

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Jan. 2, 1945. R, c, DEHMEL 2,366,603

AIRCRAFT TRAINING APPARATUS Filed Dec. 20, 1941 16 Sheets-Sheet 6 aaa 7'0 FIG 4 FIG. 7

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AIRCRAFT TRAINING APPARATUS Filed Dec. 20, 1941 16 Sheets-Sheet 7 FIG. 8

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AIRCRAFT TRAINING APPARATUS Filed Dec. 20, 1941 16 Sheets-Sheet 9 lNl/ENTOR Jan. 2, 1945. g, DEHMEL AIRCRAFT TRAINING APPARATUS l6 Sheets-Sheet 10 Filed Dec. 20, 1941 INVENTOP Jan. 2, 1945. R. c. DEHMEL AIRCRAFT TRAINING APPARATUS I T T H QWN Jan. 1945- R. c. DEHMEL 2,366,603

AIRCRAFT TRAINING APPARATUS Filed Dec. 20, 1941 16 Sheets-Sheet 12 FIG. 23

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AIRCRAFT TRAINING APPARATUS Filed Dec. 20, 1941 l6 Sheets-Sheet 13 Q n 0 9 E n OOUOOOtOliItt'I R. c. DE'HMEL 2,366,603

AIRCRAFT TRAINING APPARATUS Jan. 2, 1945.

Filed Dec. 20, 1941 16 Sheets-Sheet l4 FIG. 26.

/N VEN TOR Jan. 2, 1945. R Q DEHMEL 2,366,603

AIRCRAFT TRAINING APPARATUS Filed Dec. 20, 1941 16 Sheets-Sheet 15 I l I I Illqlarluzumnvlllllll'ifq 4 W 4 I J Jan. 2, 1945. R, c. DEHMEL 2,366,603

AIRCRAFT TRAINING APPARATUS Filed Dec. 20, 1941 16 Sheets-Sheet l6 IIIIIIII INVENTOR R/CflA/PO 6442 059/741 5 ATTORNEYS Paetaa 194sa My invention relates to anaircraft trainer for teaching student pilots to fly aircraft blindly by instruments andta practice orientation spect to radio signals. 1

In one known atype of trainer for this purpose standard aircraft instruments are operated pneuwith rematically andrthe radio signals are varied manua ally by the instructor to simulate the changes in the signals received by a pilot actually flying the course being simulated by the'student.

In my copending application Serial N0.398,590, filed June..18, 1941,-.I'havedisclosed a trainer in which standard aircraft instruments are replaced by much less; expensive devices such as tachometers with aircraft instrument dialspthese devices being operated;electric'allyein accordance with the movements of the flight 'controls. Afurtherimpropermanner,as=the;.student flies avcourse.

Certain; features. disclosed herein are common to this and said prior application.andsuch features as 1iareadisclosedei buti not}. claimed a hereirr will be claimed in my said aprior-application.-m1

tin general; the apparatusaof my invention comprisesgflight wequipm'entn 9.21 charting device; and 1 radio orientatiomequipments.ai The flightwequip: ment comprises electro mechanical facilities con: 9 trolled by an aileronwrudder, elevator, throttle and stabilizerto' give the same instrumentcreadtings as would be obtained with ancactual. air-= craft in, flightg The instrumentsduplicatelthe indications of a conventional ball bank? indicator,

rate of .turn.meter...1rate-of climbtindicator, .:altimeter, artificial horizon; air speed meter, '9; true 1 .nipu'lation.

UNITED" s A r-esw PATENT OFFICE l 2,356,603.. AiRCRAF'I', TRAINING APPARATUS "Richard QarlDehmel, Summit, N. J. QApplication December 20, 1941, Serial No.42as24 109 Claims. (01. 35-12) signal controlling device is so arranged that winddrift may be introduced, and, in addition, the beams of the range may be shifted to reproduce double beams, dog-legs or other irregularities.

Theapparatus of the trainer may be regarded as consisting of two assemblies each usable independently or in combination with the other. One of the assemblies consists 'of aircraft controls and associated circuits necessary to reproduce, on a group of instruments, the same readings as would occur on the flight instruments of an actual aircraft subjected to like control ma- This is the instrument flight training assembly. The other assembly comprises facilities for practicing in the determination of the position of an aircraft flying in a radio range. This is the orientator assembly.

For further details of the invention, reference may be made to the drawings wherein Fig. 1 is a plan view of simulated aircraft controls and a traversing table with signal and charting equipmentaccording to the present invention.

"The object of this invention is to improve the airplane control and rough air circuits of the trainer of my prior application, to simulate certain of the latest radio aids to aerial navigation, to include additional blind flying and navigation instruments and, in general, to make available, for iiighttraining, facilities which duplicate substantiallyall the conditions of actual flight on modern airways in an entirely automatic manners'o that the value of the trainer as an aid to the student is independent of the skill of the instructor in manipulating the various signal controls.

A particularly useful and important feature of I my invention is a mixing circuit which combines direction (gyro), compass: azmagnetic direction;

compass and radio ,compasstand direction appaa ,A charting device'ri provided for tracing he path of the simulated flightover the ranges The orientation equipment; comprises aone or more automatic signali:controllingmdevicesnop erated either manually by the instructor ,and/or by, ythe ,electro-mechanicalxl circuit referreda to above; fl'his signal tcontrollerstransmits signals to the pilotthat duplicate?thosewreceived in an ace eas neness.-

trainer controls in such a manner that the output of thiscircult when applied through suitable devices such as grid controlled rectifier tubes will cause motors to operate flight instruments and a signal controller. The flight instruments and signal controller give to the pilot the same visual and audible representations as he would receive from. the instruments and radio facilities of an actual airplane in flight.

- time sensitivity of the response of the trainer to aa aa mr ft ilti g i 'lfl s'htz-"intany desired: radio a signals may include i a fanx-l marker, mar er-la .e nd qca i er path mark.

/orndinglmarker beacon."

its control is made variable to simulate difierent types and: sizes of airplanes by providing a varithe fiightinstruments and in the case of a movable trainer. for producing the motion of the trainer, s v v Another feature of the invention is an improved means for simulating in a very simple and inexpensive manner the delay in the response of an actual airplane to the movement of its controls.

As a further approximation to the conditions of actual flight, the cabin of the trainer is provided with means for simulating the sounds of an airplane in flight, these sounds being varied in pitch and intensity as the flight controls are operated.

A very useful and important feature of the invention is a novel means for simulating radio range signals, blind landing glide beams and radio marker signals and causing these to vary entirely automatically as the pilot operates the trainer, the variations producing a replica of the radio signals that the pilot would receive were he in actual flight over an airway radio range.

According to a further feature of the invention interlaced and overlapping radio patterns simulating those received from two or more transmitting stations may be set up by means of a plurality of signal controllers all operated automatically according to the course being "flown by the student.

Another important feature of my invention comprises means for simulating a, radio compass, a radio direction finder and a continuous radio direction indicator with the point of balance of each being changed by movement of the trainer elements.

These and many other features of the invention, such as a novel means of introducing the effects of wind drift, will be more clearly understood from the following detailed description of the construction and operation of my trainer and the accompanying drawings in which:

Fig. 1 is a plan view of the aircraft simulating apparatus, its controls and a traversing table with signal control and charting equipment.

Fig. 2 is an elevation of the apparatus of Fig. 1 partly in section.

Fig. 3 is a front elevation of the instrument panel of Fig. 1 and Fig. 2.

Fig. 4 is a diagrammatic perspective view and wiring of the artificial horizon.

Fig. 5 is the circuit for steering control.

Fig. 6 is the circuit for altitude control.

Fig. 7 is the circuit for rough air control.

Fig. 8 is a vertical section of the controller on line 8-8 of Fig. 1.

Fig. 9 is a plan view of the controller, showing the operating arm and contacts in one position.

Fig. 10 is a partial view of Fig. 9 showing the contacts in another position.

Fig. 11 is a sectional view on line il-il of Fig. 10.

Fig. 12 is. a. sectional view on line i2--I2 of Fig. 10.

Fig. 13 is a sectional view on line iii-l3 of Fig. 8

Fig. 14 is'a sectional view on line il-ll of Fig. 8.

Fig. 15 is a sectional view on line l5l8 of Fig. 8.

Fig. 16 is a sectional view on line l8-i8 of Fi 8.

Fig. 17 is a circuit for the limit control of the arm shown on Fig. 9.

Figs. 18, 19, 20, 21 and 22 are the control and signal circuits of controller, Fig. 8.

Fig. 23 is a perspective view of the mechanical controls behind the instrument panel Fig. 3.

Fig. 24 is an alternate method of control to Fig. 8.

Fig. 25 is a plan view of the traversing table showing an alternate use of the controller Fig. 8.

Fig. 26 is an elevation view of Fig. 30.

Fig. 27 is a detail sectional view of the magnetic compass.

Fig. 28 is a top plan view of the magnetic compass.

Fig. 29 is a partial sectional view of the magnetic compass.

Fig. 30 is a schematic circuit for the magnetic compass.

Figure 31 is a sectional view of the pantograph recording pencil support on line ll-4i of Figure 1.

Figure 32 is a sectional view of the charting head on line 32-32 of Figure 1.

Figure 33 is a somewhat diagranmiatic front elevational view showing further details of certain instruments shown on the panel I of Figure 3.

Figure 34 is a wiring diagram of certain features shown in Figure 8. 1

Referring to the drawings, and more particularly to Figures 1 and 2, the trainer comprises aircraft controls I II, I I, I3 and 0, Fig. 2, circuits Figs. 5, 6 and 7 operated thereby; and flight indicators consisting of a flight instrument group, Fig. 3.. a course charting device M, Fig. 1, and signal controllers i6 and I6 each of which is responsive to the circuits. The output elements of the control circuits to which the flight instruments, the course charting head and signal controller respond comprise three motors, namely, the air speed motor ASM, the steering motor SM and the altimeter motor AL'I'M. These matters will be more fully referred to and their function and the element responsive thereto will be more fully detailed below. For the sake of brevity, the instrument flight training assembly and the orientator assembly will be described in combination, it being clear that either may be used alone. The two assemblies are mechanically linked togather for combination use by the ASM motor shaft 82, Figs.2 and 31 and the SM steering motor shaft 8 i Figs. 1 and 2.

The course charting head M, Figs. 1, 2 and 32, is steerably mounted in the pantograph Ii at the sleeve. 18, Fig. 32. The position of the head ll represents the location of the aircraft on the range, the orientation of the head is the true course and the velocity of the head is proportional to the air speed. Mounted in the joint 66,

Fig. 1 is a path tracing pencil 6'! which plots the course in reduced scale on map 19, Fig. l.

The tractive wheel 65, Fig. 32, is rotated on its own axis 89 by the air speed motor ASM, 2 which is responsive to controls i0, ii, is and so through the circuits of Fig. '7. The motor ASM is secured to the underside of the traversing table 8. The ASM motor drivesthe wheel 55 through the reduction gearing l8 and H, Fig. 31, the shaft 82, sprocket 12, the chain 13, Fig. 1 the driven sprocket 14, Figs. 1 and 32, and the flexible shaft 15 which transmits power through the miter gears 16 to the tractive wheel which moves the head it.

The motor ASM also drives the air speed indicator I Fig. 3 through the shaft 41 and pulleys 48 and 50, Figs. 2 and 33. The air speed indicator l is a tachometer of any standard design but calibrated in terms of air speed units. The tachometer construction may be the revolving magnet type commonly used for automobile speedometers. However, a vibration tachometer,

or an electrical tachometer could beused asalternatives.

To simulate turning oi the aircraft. the fsteerg ablecourse charting head l4 Figs..1 and '32 is,

rotated by the steering motor SM..Figs 1,3. 23, said motor being responsive to controls II,

manner to be more particularly describ 4 inatter. Mechanical connection betweent tor SM and head It is through the,.gear.. ,train 439 and 332, Figs. 2 and 23, and the shafti l andv the miter gears 80, Fig. 31, the driving sprocketg II, the chain 82, Figs. 1 and 31, and -tha driven sprocket 83, Figs. 1 and 32. Directly connectedito the motor SM is the rate of turnindicator 2, g

3 and 23. This indicator, like the air speed intion and is calibrated to show the turning lrate in Figs. 3 and 33, responsive to controls. |li, ,ll through the circuits of Fig.7.

Driven by the shaft 6|, Figs. 1, ,2 and 23 is;

compass and dial 5, Figs. 2 and 23. ,This opera tion is described in fuller detail hereinafter...

asmuch as the ratio of the miter gearstfl and" the sprockets 8| and 83 Figs. 31 andfl, and. the

"en An average air speed control "0, F18 1 h d respect to table Accor ,z illia aa ira' station including h s n 388. a d I m mounted on Qspring'sj v r. met

gears 320, 32l Fig. 23 and other gears or the .train 1 total unity, the compass 5 indicates the heading of the course charting head l4. a

The course charting device above and in the claims may serve as an indicat ing instrument or it may be used ior re'cord g,

the flight by inking its tracing wheel. V

The ASM motor drives the course, ch

head l4 and the air speed meter I,.Fig...3, at a rate proportional to the forward speed of mean; plane. The steering motor SM orients the course charting head l4, operates the rate of turn indicator 2, Fig. 3; and the compass 5,..Fig. 3.; The. altimeter motor ALTM drives the rate oficlimb indicator 3 and the altimeter 4 at arat'o 'cprre sponding to the vertical air speed of theairplane. I The rate of climb meter 3 Fdgs."2,\3 and 23, "is operated by direct connection'tothe altitude moe. tor ALTM, Figs. 1, 2 and 23, which is responsive to controls III, II and I3 through the circuitspf Figs. 6 and 7. The meter 3 is a tachometer. have: ing two-way deflection from zero an calib ated, to represent rate of climb. Also drivenflb V he .Fig. 23 is the altimeter 4. the indicatingelementoif motor ALTM, through gearing 33l indfggli,

which is a simple pointer.

Means other than tachometers couldi.bet e rn-. ployed for indicating airspeed, rate ofjturmand. rate of climb. For example, it islobviou that' galvanometers having suitable scalejc'alibra on;

markings and connection as for instance." the motors ASM, SM or ALTM would ser, factorily as airspeed. rate of turnjand climb meters. I could also use other me tuated by an intermediate circuit suc 5, 6 and '7 which are responsive to controls and I3. d

Other instruments of my apparatusas in Figs. 1, 3, 23 and 24, are attenuatorAT adjusting the strength of the radio ahgefsi nails} 2. meter RPM Figs. 1 and 7 depicting an tachometer duplicate rough air switches 49 for actuating a featureof the our:

causes all instruments to have agitateddeiiect ons such as occur with aircraft flying in rough weath.

ionicoconductioni an term thermionicwvalvltor he. ik'iexpressioniisi .P. W source 405 'and -has a secondafy winding which heats the filaments of vacuu .Lhave foundxtha a exceptionally advantageous control :circuit.;may. beiplovided by a novel combinationrcomprising;essentially:fpotentiometers and thermionic valves. this specification and rzlthe following? claims: i themterins fvacuum actual high vacuumfdevicestfunctioningybyigelecev tron emission e'and control vand/or gaseous dis-" charge tubes-silence. thyratronisgiiunotioning by:

intended. asi a fgener'ic eexpresslon 6i complemen the s'ai d'device and those .of asimi lan chai'acteir whe her using i cold' emitter.

circuits i hodes I i 14i satin" i f nd the oath;

grid bias voltage to superimpose an alternating current on the steady current to plate 4! 4.

The plate current with its superimposed alternating current flows through section 4i|i of the push-pull primary winding of transformer III at an amplitude dependent on the position of slider 403 which in turn depends on the position of the rudder il, Fig. 1. Negative bias voltage for the grid 4| 1 is obtained from slider 40l of potentiometer 400 through resistance 8 and the grid return connection to the cathode extends through the balancing resistance 3, wire 3 and transformer winding 401. The current to plate 420 is therefore modulated by the alternating voltage of winding 401 in a manner similar to that employed for modulating the current'of plate 4 and this modulated current passes through section 42l of transformer 4l6. It will be clear that if the voltages at sliders 40l and 403 are equal, which is the condition when the rudder and aileron are centrally disposed, the superimposed alternating currents from plates 4 and 420 will be equal in magnitude but opposite in phase and will therefore induce no voltage in the secondary windings 422 and 423 of transformer 4i6. However, any displacement of either slider 40I or 403 will cause an unbalance in the currents through plates 4| 4 and 420 and therefore a change from winding 42i to predominate and induce a potential across windings 422-423 of instantaneous polarity conforming to the degree of prerlomination of the current in winding 42l over that in winding 5.

Elements 426 and 421 are thyratron vacuum tubes which become conductive, as is well known, with depression of their control grid potentials. Accordingly thyratron 426 or 421 will flre" depending on which of the grids 424 and 425 is made less negative than normal by the instantaneous potentials induced across winding 422- 423. Motor SM Fig. 5, is the steering motor which is also shown in the assembly, Figs. 1, 2, and 23. Inasmuch as the potentials through this motor to the plates 428 and 429 of thyratrons 426 and 421, respectively, are maintained in constant phase relation with respect to potentials induced through transformer 0 due to their common connection to the supply source 406, the point in the voltage cycle at which either tube is "fired" is dependent on the magnitude and phase of the voltage across winding 422423 of transformer H6. The motor SM may accordingly be caused to operate in either direction at any desired speed by deflecting slider I or 403.

The connection of the transformer winding 401 in the grid bias circuit and the use of a pushpull primary on transformer 4l8 to cause, during unbalances of plate current in tube 409, the induction across windings 422'and 423 of alternating voltages of proper phase and magnitude to cause the motor SM to respond to deflection of sliders 4M and 403, is an important and very useful feature of my invention. Throughout the specification and the claims, wherever it occurs,

the term "parameter" shall be expressly understood as defining such circuit variants as phase, magnitude of the potential or current of the energizing voltage, and it shall also designate the frequency of alternating currents herein specified Any deflection of sliders 40! and 403 in the same direction increases the unbalance in the currents at plates 4 and 420 and results in an increase in speed of the motor SM. It is evident therefore that the steering motor SM responds to operation of either the rudder or the aileron or both. Conjoint operation of these controls resultin greater turning rate of the motor SM than would occur with either the rudder or aileron deflected separately by a given amount. Deflections of the sliders "I and 403 which produce equal voltage changes on the grids 4H and 4" cause no change in balance of the currents at plates 4 and 420 and no effect on the motor SM. Aeronautical maneuvers such as slips and skids may therefore be simulated inasmuch as the opposite control dispositions required in these maneuvers result in holding the turning rate of the steering motor SM at zero or allowing only rotation to the extent that the controls are disproportionately defleced in opposite directions;

While Fig. 5 illustrates a double triode vacuum tube at 409, two separate vacuum tubes may of course be employed with comparable operation. Moreover, multi-grid vacuum tubes also may be used in which grids 4H and 4H serve as the control grids.

The difference in the control responses of heavy and light airplanm may be simulated by the con-'- trol circuit of Fig. 5 by adjusting the sensitivity of the circuit to any desired value in various ways such as by shunting the primary (or secondary) of transformer 0 with an adjustable rheostat 430.

Another feature of the circuit of Fig. 5 is the delay in response of the circuit to movement of slider 40l which is operated by aileron i0, Fig. 1. This introduction of delay in response is desirable in that such lagging action is a characteristic of actual aircraft. The introduction ofthis delay is accomplished by a condenser 43l in combination with a resistance 4|8. By making the resistance 8 variable'as shown in Fig. 5 the degree of delay may be altered as desired. Slight leakage resistance to condenser 43l as shown at 432 may beintroduced to slowly discharge condenser 43l and thereby reduce the speed of the SM motor which makes necessary the retention of a small continued pressure on the aileron to retain some charge on condenser 43! so as to hold the steering motor SM operative. The leakage of condenser 43l and the tendency thereby introduced to reduce the speed of the SM motor, resemble the recovery tendency of actual aircraft in shallow turns.

A further feature of the circuit, Fig. 5, is the rheostat 433-434 which becomes effective during opposite operation of the rudder and aileron controls to reduce the degree of delay in circuit response to aileron operation by progressively shunting the time constant resistance 4l8 as opposite deflection of the controls is increased.

- This simulates the characteristic of an airplane to hang" on its controls during opposite control disposition. In Fig. 5, slider 435 operates conjointly with slider 40! to which it is also electrically connected. Slider 435 contacts the rheostat elements 433 or 434 only while the slider 435 is deflected from its central position. Slider 

